[PATCH v7 2/4] drm/xe/vf: Fix GuC FW check for VF migration support

[Tomasz Lis <tomasz.lis@intel.com>]

The check whether GuC ABI version meets requirements shall be
performed after said version is received from GuC.

Doing it in wrong order was triggering a warning:
xe 0000:00:02.1: [drm] Assertion `gt->sriov.vf.guc_version.major` failed!

With this change, dislodge part of the VF migration support check
and moved it to after GuC handshake.

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Tested-by: Matthew Brost <matthew.brost@intel.com> #v1
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6349
Fixes: ff1d2b5e3d28 ("drm/xe: Read VF GMD_ID with a specifically-allocated dummy GT")
Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
---
v2: Use xe_sriov_vf_ccs_migration_bb_needed()

v3: Update commit message, move check funct to ccs module (Michal),
 rename xe_sriov_vf_migration_disable(), remove its duplicate

v4: Limit scope of some functions to xe_sriov_vf_ccs file,
 switched 'Fixes:' tag to a different commit (Michal)

v5: Squashed with "Helper for telling whether CCS migration BBs are
 needed", added kerneldoc, moved location of some checks (Michal)

v6: Typo, equivalent gt getter and exposing some conditionals (Michal)

 drivers/gpu/drm/xe/xe_sriov_vf.c     | 33 ++++++++------------
 drivers/gpu/drm/xe/xe_sriov_vf.h     |  1 +
 drivers/gpu/drm/xe/xe_sriov_vf_ccs.c | 46 ++++++++++++++++++++++++++--
 3 files changed, 57 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.c b/drivers/gpu/drm/xe/xe_sriov_vf.c
index 0d8135f3927c..13d6c094ae8f 100644
--- a/drivers/gpu/drm/xe/xe_sriov_vf.c
+++ b/drivers/gpu/drm/xe/xe_sriov_vf.c
@@ -133,7 +133,12 @@ bool xe_sriov_vf_migration_supported(struct xe_device *xe)
 	return !xe->sriov.vf.migration.disabled;
 }
 
-static void vf_disable_migration(struct xe_device *xe, const char *fmt, ...)
+/**
+ * xe_sriov_vf_migration_disable - Turn off VF migration with given log message.
+ * @xe: the &xe_device instance.
+ * @fmt: format string for the log message, to be combined with following VAs.
+ */
+void xe_sriov_vf_migration_disable(struct xe_device *xe, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list va_args;
@@ -156,22 +161,13 @@ static void vf_migration_init_early(struct xe_device *xe)
 	 * supported at production quality.
 	 */
 	if (!IS_ENABLED(CONFIG_DRM_XE_DEBUG))
-		return vf_disable_migration(xe,
-					    "experimental feature not available on production builds");
+		return xe_sriov_vf_migration_disable(xe,
+				"experimental feature not available on production builds");
 
 	if (GRAPHICS_VER(xe) < 20)
-		return vf_disable_migration(xe, "requires gfx version >= 20, but only %u found",
-					    GRAPHICS_VER(xe));
-
-	if (!IS_DGFX(xe)) {
-		struct xe_uc_fw_version guc_version;
-
-		xe_gt_sriov_vf_guc_versions(xe_device_get_gt(xe, 0), NULL, &guc_version);
-		if (MAKE_GUC_VER_STRUCT(guc_version) < MAKE_GUC_VER(1, 23, 0))
-			return vf_disable_migration(xe,
-						    "CCS migration requires GuC ABI >= 1.23 but only %u.%u found",
-						    guc_version.major, guc_version.minor);
-	}
+		return xe_sriov_vf_migration_disable(xe,
+				"requires gfx version >= 20, but only %u found",
+				GRAPHICS_VER(xe));
 }
 
 /**
@@ -193,12 +189,7 @@ void xe_sriov_vf_init_early(struct xe_device *xe)
  */
 int xe_sriov_vf_init_late(struct xe_device *xe)
 {
-	int err = 0;
-
-	if (xe_sriov_vf_migration_supported(xe))
-		err = xe_sriov_vf_ccs_init(xe);
-
-	return err;
+	return xe_sriov_vf_ccs_init(xe);
 }
 
 static int sa_info_vf_ccs(struct seq_file *m, void *data)
diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.h b/drivers/gpu/drm/xe/xe_sriov_vf.h
index 4df95266b261..e967d4166a43 100644
--- a/drivers/gpu/drm/xe/xe_sriov_vf.h
+++ b/drivers/gpu/drm/xe/xe_sriov_vf.h
@@ -14,6 +14,7 @@ struct xe_device;
 void xe_sriov_vf_init_early(struct xe_device *xe);
 int xe_sriov_vf_init_late(struct xe_device *xe);
 bool xe_sriov_vf_migration_supported(struct xe_device *xe);
+void xe_sriov_vf_migration_disable(struct xe_device *xe, const char *fmt, ...);
 void xe_sriov_vf_debugfs_register(struct xe_device *xe, struct dentry *root);
 
 #endif
diff --git a/drivers/gpu/drm/xe/xe_sriov_vf_ccs.c b/drivers/gpu/drm/xe/xe_sriov_vf_ccs.c
index 790249801364..797a4b866226 100644
--- a/drivers/gpu/drm/xe/xe_sriov_vf_ccs.c
+++ b/drivers/gpu/drm/xe/xe_sriov_vf_ccs.c
@@ -10,6 +10,8 @@
 #include "xe_device.h"
 #include "xe_exec_queue.h"
 #include "xe_exec_queue_types.h"
+#include "xe_gt_sriov_vf.h"
+#include "xe_guc.h"
 #include "xe_guc_submit.h"
 #include "xe_lrc.h"
 #include "xe_migrate.h"
@@ -260,6 +262,45 @@ int xe_sriov_vf_ccs_register_context(struct xe_device *xe)
 	return err;
 }
 
+/*
+ * Whether GuC requires CCS copy BBs for VF migration.
+ * @xe: the &xe_device instance.
+ *
+ * Only selected platforms require VF KMD to maintain CCS copy BBs and linked LRCAs.
+ *
+ * Return: true if VF driver must participate in the CCS migration, false otherwise.
+ */
+static bool vf_migration_ccs_bb_needed(struct xe_device *xe)
+{
+	xe_assert(xe, IS_SRIOV_VF(xe));
+
+	return !IS_DGFX(xe) && xe_device_has_flat_ccs(xe);
+}
+
+/*
+ * Check for disable migration due to no CCS BBs support in GuC FW.
+ * @xe: the &xe_device instance.
+ *
+ * Performs late disable of VF migration feature in case GuC FW cannot support it.
+ *
+ * Returns: True if VF migration with CCS BBs is supported, false otherwise.
+ */
+static bool vf_migration_ccs_bb_support_check(struct xe_device *xe)
+{
+	struct xe_gt *gt = xe_root_mmio_gt(xe);
+	struct xe_uc_fw_version guc_version;
+
+	xe_gt_sriov_vf_guc_versions(gt, NULL, &guc_version);
+	if (MAKE_GUC_VER_STRUCT(guc_version) < MAKE_GUC_VER(1, 23, 0)) {
+		xe_sriov_vf_migration_disable(xe,
+					      "CCS migration requires GuC ABI >= 1.23 but only %u.%u found",
+					      guc_version.major, guc_version.minor);
+		return false;
+	}
+
+	return true;
+}
+
 static void xe_sriov_vf_ccs_fini(void *arg)
 {
 	struct xe_sriov_vf_ccs_ctx *ctx = arg;
@@ -292,9 +333,10 @@ int xe_sriov_vf_ccs_init(struct xe_device *xe)
 	int err;
 
 	xe_assert(xe, IS_SRIOV_VF(xe));
-	xe_assert(xe, xe_sriov_vf_migration_supported(xe));
 
-	if (IS_DGFX(xe) || !xe_device_has_flat_ccs(xe))
+	if (!xe_sriov_vf_migration_supported(xe) ||
+	    !vf_migration_ccs_bb_needed(xe) ||
+	    !vf_migration_ccs_bb_support_check(xe))
 		return 0;
 
 	for_each_ccs_rw_ctx(ctx_id) {
-- 
2.25.1